The rifle was offered with a walnut or a beech stock, one was a 1516 and the other was the 1515, so they marked the actions with both model numbers since they were identical guns except for the stock wood. They no longer do this, they are all marked 1516's now.
They did the same with the 22LR's, they were marked 1415-1416 for a while. They are all marked 1416's now.
